SAN FRANCISCO — Roku is getting into an Internet video-streaming stick fight with Google’s Chromecast.
Like the similarly shaped Chromecast, Roku’s thumb-sized device plugs into a TV’s HDMI port and feeds Internet video through a Wi-Fi connection.
The Roku device, revealed Tuesday, sells for $50 compared with $35 for the Chromecast. The low price and Google brand cachet have made Chromecast popular since its release last summer.
Google hasn’t divulged Chromecast sales, but the stick ranks as the second-most popular electronics item on Amazon.com. Only Amazon.com Inc.’s own Kindle Paperwhite e-reader outsells the Chromecast in the website’s electronics section.
Some of the Chromecast’s sales may have come at the expense of Roku’s lineup of set-top boxes for showing Internet video. The latest box, the Roku 3, sells for $99 and ranks fifth in Amazon.com’s electronics sales.
Overall, Roku Inc., based in Saratoga, Calif., says it has sold more than 8 million video-streaming devices since its first box hit the market nearly six years ago.
Apple TV is Roku’s biggest rival in Internet streaming boxes. Apple Inc. says it has sold 13 million of those boxes.
Roku has been selling another video-streaming stick since 2012, but that device only works on TVs with mobile high-definition, or MHL. TVs with an MHL port are still a specialty item. Virtually all TVs sold during the past few years have an HDMI outlet.
Although Roku’s HDMI stick costs more than the Chromecast, the company is counting on its broader selection of apps to give it an edge with consumers. Roku has more than 1,200 apps, or ‘‘channels,’’ that stream video.